Michelson stellar interferometer
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Michelson stellar interferometerAny of a series of interferometers constructed by A.A. Michelson to measure the small angular dimensions of stellar objects, such as a star's apparent diameter or the angular separation of a double star. In the original version, a telescope objective was covered by a screen that was pierced with two parallel slits of adjustable separation. The components of a double star (or the two halves of a stellar disk) will each produce a set of interference fringes as a result of the double slit. By varying the slit separation, d , the bright fringes of one pattern can be made to coincide with the dark fringes of the other so that a continuous line of light is seen; the angular dimension is then proportional to d . Michelson was able to measure the diameters of several nearby stars down to about 0.01 arcsec, including that of the supergiant Betelgeuse. Much more sensitive measurements can now be made with modern optical interferometers.
Michelson stellar interferometer[′mī·kəl·sən ¦stel·ər ‚in·tər·fə′räm·əd·ər]
An instrument for measuring angular diameters of astronomical objects, in which a system of mirrors directs two parallel beams of light into a telescope, and angular diameter is determined from the maximum distance between the beams at which interference fringes are observable.